At a recent public meeting on U.S. Climate Alliance in New York, Brown stated, “We're doing something in the face of inaction.

“Eventually, Washington will join with us, because you can't deny science forever, you can't deny reality. And the reality is climate change is occurring."

With a zero-emissions mandate currently in place, California is one of the U.S. states that’s fully committed to carrying out the objectives of the Paris Agreement – which is an ambitious project from the United Nations aiming to tackle the problems caused global climate change.

One of the specific targets of the agreement is to stop the continued increase in global temperatures by reducing greenhouse gas emissions as much as possible.

The U.S. was highly criticised in June however when President Trump announced that he was going to withdraw the United States from the Paris Agreement altogether.

Jerry Brown’s announcement follows a similar diktat from the British and French Governments, suggesting electric vehicle adoption may be closer than we think.

And, while nothing has been formally announced regarding the banning of the internal combustion engine in California, it’s clear that the movement is on the table and is seemingly a case of not if, but when it’ll happen.

What are the UK's plans?

The government published a draft air pollution plan in May, outlining its plans to cut the NO2 emissions with one of the expected proposals including a scrappage scheme. In the final report though, this was not included and described previous scemes as "poor value for money."

Local authorities will be able to implement these changes imminently, with a £40-million fund of a total £255-million pot and will also be able to use the money to implement new technologies, change road layouts and encourage the use of public transport.

It could also see the implementation of emissions charging zones to help curb NO2 levels in the worst affected areas.

France is also looking to ban the sale of any car that uses petrol or diesel by 2040, with an overall aim to be completely carbon-neutral by 2050.